That’s the outlier DAMA/LIBRA experiment:
For decades, now, scientists have been searching valiantly for the elusive particle that might make up some or even all of the dark matter. While the astrophysical evidence supporting the existence of dark matter is overwhelming, every experiment designed and built to directly detect whatever particle might be responsible for dark matter has come up empty.
Every experiment, that is, except one: the DAMA/LIBRA experiment. While other experiments that are far more sensitive — including SuperCDMS, XENON, Edelweiss, LUX, and many others — have only detected negative results down to extreme precisions, DAMA/LIBRA has continuously observed a significant signal for about 20 years. At last, the critical test has been performed: a completely independent team, ANAIS, has carried out an identical experiment to DAMA/LIBRA, replicating the study and testing its validity. With three complete years of data collected, ANAIS has ruled out the DAMA/LIBRA results in a model-independent way to better than 99% confidence. The world’s most controversial dark matter experiment has been busted, and it’s an incredible success for the scientific method.
Ethan Siegel, “Goodbye, DAMA/LIBRA: World’s Most Controversial Dark Matter Experiment Fails Replication Test” at Forbes
Siegel offers an inside look at the details. While the finding is doubtless a success for the scientific method, it must be frustrating for those physicists who need dark matter to exist in order to make cosmology understandable — but can’t find any.
See also: Discover: Even the best dark matter theories are crumbling
Researcher: The search for dark matter has become a “quagmire of confirmation bias” So many research areas in science today are hitting hard barriers that it is reasonable to think that we are missing something.
Physicists devise test to find out if dark matter really exists
Largest particle detector draws a blank on dark matter
What if dark matter just doesn’t stick to the rules?
A proposed dark matter solution makes gravity an illusion
and
Proposed dark matter solution: “Gravity is not a fundamental governance of our universe, but a reaction to the makeup of a given environment.”